It is very desirable for fuel cells to generate a constant flow of electrical power. Uneven or interrupted flow of electrical power may result in failure of the device being powered by the fuel cell. To obtain a more constant generation of electrical power some fuel cells employ a moving anode configuration. The moving anode maintains the anode at a predetermined distance from a cathode by using standoffs extending between the anode and the cathode, and by applying a biasing force to the anode. Use of the biasing force maintains the anode at a predetermined distance from the cathode even as electrolyte passes therebetween. Meanwhile, an oxidizing agent is exposed to the cathode which in turn consumes the anode material. Without the biasing force applied, consumption of the anode material would cause an increase in the distance between the anode and cathode and accordingly cause fluctuations in the generation of electrical power.
In order to ensure that the moving anode is maintained at a constant distance from the cathode, the anode is secured to a boot usually made of a rubber-like material. The boot seals around one side of the anode and is secured to the fuel cell housing. The boot provides a seal between the electrolyte flowing between the anode and cathode and the coolant flowing on the opposite side of the anode. If the seal between the electrolyte and the coolant is breached, the fuel cell becomes ineffective and eventually fails.
In the past, attachment of the boot to the anode included bonding the boot to the anode with various types of adhesive, and/or plating the anode with nickel or other alloys and then bonding the anode to the boot. In addition to bonding the boot to the anode it is also required that a lead be connected to the anode to complete the electrical connection for the fuel cell. Connection of the lead must be accomplished without degrading the seal between the boot and the anode. This connection of the lead has been accomplished by using conductive epoxy, nickel-plating the anode and then soldering the lead thereto or by using deep solder-filled holes in the top of the anode in which the lead is encased. Unfortunately, these attempts at bonding the boot to the anode with a lead connected thereto only last about six hours which is unsuitable for long-life use. It has been found that the electrolyte, which is naturally attracted to the anode material, attacks the plating and/or bonding material disposed on the anode and destroys the bond between the boot and the anode, which in turn causes failure of the fuel cell. It will also be appreciated that as the anode material is consumed, the rigidity of the anode is lost which causes deviations in the spacing between the anode and cathode.
In light of the foregoing, it is evident that there is a need in the art for a sealed anode assembly within a fuel cell that is robust and long-lasting. Moreover there is a need in the art for secured anode within a fuel cell for generating a constant amount of electrical power.